public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            MyDialogFragment myDialogFragment = new MyDialogFragment();
            myDialogFragment.show(getSupportFragmentManager(), MyDialogFragment.TAG);

        }
    });

    findViewById(R.id.background).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Log.e("wrong", "clicked!!!!---------------");
            Toast.makeText(MainActivity.this, "Click!", Toast.LENGTH_LONG).show();
        }
    });
}

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setCancelable(false);
}

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
                         @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.my_dialog_layout, container, false);
    getDialog().setCanceledOnTouchOutside(false);
    return view;
}

@Override
public void onResume() {
    Window window = getDialog().getWindow();
    Point size = new Point();
    Display display = window.getWindowManager().getDefaultDisplay();
    display.getSize(size);
    window.setLayout((int) (size.x * 0.8), WindowManager.LayoutParams.WRAP_CONTENT);
    window.setGravity(Gravity.CENTER);
    super.onResume();
}